What is the most powerful antagonizing NPC you have ever made?
For me it was a construct girl by the name of InZe (Infinite Zero). On top of the fact that she had a +5 level adjust, she had 1,000 (yes you saw that right) character levels and insane amount of divine ranks (she was never meant to be directly fought, but there are some people I game with that feel that they MUST fight the bad guy). In InZe's defense, she isn't really a bad person, she is more like Chaotic Neutral with Chaotic tendencies. Also VERY insane, she was created from the destruction of entire universe. Her personalities are all but uncountable and you can see her cycle throught the personalites by watching her eyes.
Looks similar to this but not exactly the same. I guess you could say she was an entire universe in human(iod) form. Eventually I abandoned the character as I gave up on the campaign (I realized I would have to HEAVILY railroad the campaign, and that is fun for no one). I can discuss more on this topic if you want, but I'd also like to hear what you guys have made in your campaigns.